Four House Democratic challengers are pledging not to accept corporate PAC money in their campaigns, earning them the endorsement of the End Citizens United PAC.

End Citizens United’s executive director, Tiffany Muller, said the challengers’ decision marks a shift among candidates who see campaign finance overhaul as a winning message.

“I think what we’re seeing is a trend about voters feeling shut out of the system and feeling more and more disconnected from their government,” Muller said.

The PAC is named after Citizens United v. FEC — the 2010 Supreme Court decision that has allowed corporations and unions to spend unlimited amounts of money on politics — and it backs candidates who want to overhaul campaign finance laws.

The PAC is endorsing four candidates, all of whom are taking on GOP incumbents targeted by the Democratic Congressional Campaign Committee. Those candidates are:

Both Brindisi and Crow have accepted PAC money, just not from corporations. Some of that money has come from leadership PACs, including the PAC associated with DCCC Chairman Ben Ray Luján, D-N.M.

Muller said there is a distinction between accepting money from corporations and from other PACS.

“We’re not against PACs. We are one,” Muller said. “We believe PACs are a great way for small dollar donors to come together and really make a difference.”

Corporate PACs, on the other hand, are “fueled by big corporations, and they’re investing in a race because they’re seeking to influence votes and policies that affect their bottom line,” Muller said.

The endorsements are in districts that took divergent paths in the November presidential election. President Donald Trump carried the New York and New Jersey districts, while Democrat Hillary Clinton carried the Colorado and Minnesota seats.

Muller said the differences among the districts show that overhauling the campaign finance system is a salient message across the political spectrum.

“This is really an issue that we have seen resonate across all political ideologies and across all kinds of different districts,” she said. “The only place this is partisan is in the halls of Congress.”

Muller pointed to the group’s polling that suggests this issue is also important to independent voters, who will be key as Democrats look to flip 24 seats to regain control of the House.

The group’s national poll from 2016 showed that 44 percent of independent voters rate “reducing the influence of special interest money in government and elections” as a top priority.

Founded in 2015, End Citizens United has already endorsed three other House challengers this cycle — Randy Bryce in Wisconsin’s 1st District, Chrissy Houlahan in Pennsylvania’s 6th District and Paul Davis in Kansas’ 2nd District — as well as Senate challengers Jacky Rosen and Beto O’Rourke. Rejecting corporate PAC money is not a requirement for the group’s endorsement, but shows the candidates are dedicated to the issue.